Worldbuilding - History

For the purposes of this section, "History" refers to the parts of history
which have been permanently recorded in some fashion which is not subject to
rapid degredation or subjective interpretation; typically the written word.

Most of your setting's "present day" existence will be directively defined
by History. That said, it's also the hardest part if your world's history for me
to provide useful advice.

When writing your world's history, consider what you have already established
about your setting. Where did your races spring forth from the Mythos period? When
and how did they begin to record history? What have they done since then?

Since writing a detailed wordlwide history is an exercise in madness, focus
on the biggest, most important points. Major power players like kings, emeperors,
religious prophets, world-shaking monsters. Big wars between major civilizations
with border-shaping outcomes. Plagues, massive famines. Exploration, discovery,
science. Consider the big things you know about world history. The population of
some town in Europe in 1491 is fairly useless trivia, but knowing the name of
William the Conquerer and what he did is a great example.

Examples

Example 1 - Shadow of Olympus

I think that Shadow of Olympus works best as a setting with a fairly short
history. After the gods set humans loose upon the material plane, they spread out
a bit, formed tribes, and almost immediately started fighting amongst themselves.
We can use real-world greek city states lik Athens, Crete, and Sparta, which works
really well since we're using real-world Greek mythology and geography, and also
gives us a lot of real-world historical rivalries to lean on. We can add in some
cool supernatural events like wars with elementals or demons, and make cool
characters like Odysseus and Achilles real historical figures, which will give us
enough of a history to use without making it feel like everything interesting has
already happened.

Example 2 - Space Grease

Since Space Grease is a real-world future setting, most of our History is already
written. What took place between today's date and the beginning of Space Grease is
of more interest. How did humans move to the star en masse? Who is in charge, and
how did they come to be? When did robots gain sentience? All excellent points to
address.

Example 3 - Heroes of Tonesvale

Heroes of Tonesvale is an alternate-reality Earth, so most of History can be
used with minimal modification. Major figures in history may have been supers, and
superpowered heroes may have taken key positions in historical armies, law enforcement,
or possibly even politics. Imagine if George Washington had superhuman strength.
It would be awesome, and would have made for a few cool stories, but the majority
of american history would have been largely the same.